The status of alpha and beta haemolysins in Nigerian blood donors.

Six hundred and two blood donors were screened for alpha (alpha) and beta (beta) haemolysins using standard tube technique at 37 degrees C for 1 hour. The prevalence of beta haemolysin in group A donors was 12.1% while that of alpha haemolysin in group B donors was 5%. 21.4% of the donors had alpha, beta and alpha + beta haemolysins in their sera. The frequency of group O donors with alpha only in their sera was 5.7% which is comparable to that in B donors. beta haemolysin occurring alone in group O subjects was 8.6% which is not statistically significant from the 12.1% prevalence in A donors (P greater than 0.05). Total haemolysin frequency in O donors was 30.6% which is significantly higher than the 21.4% prevalence of the entire donors (P less than 0.005). Summation of occurrence of beta haemolysins appearing singly in group O donors (14.3%) is comparable to the prevalence of alpha + beta appearing concurrently (16.3%). Rhesus D distribution had no significant influence on prevalence of alpha and beta haemolysins. There was no significant difference between the different age groups of the donors. It is concluded that the use of O blood for A or B recipients be discontinued considering the high frequency rate of 30.6% for alpha and beta haemolysins in group O donors.